Isn't the idea of a single access protocol simple enough that one could be specified, and a socket reserved for it, before the proposed mail protocol becomes official? The result would be that MP could be the first protocol implemented under UULP (or whatever it is to be called), and the other protocols could be "moved" as soon as any problems in the official specifications could be worked out, and at the convenience of implementors.
The single access protocol might have the following commands:
USER PASS ACCT MAIL FTP RJS DRS (?) HELP (?) BYE
following Jim White's idea of nested command and reply spaces.
This doesn't address the question of "what is free", or of the interrelationships between the various protocols, but it doesn't make those problem any worse, only a little different.
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